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[07:00:00] VICTOR BLACKWELL, CNN ANCHOR: New punches thrown in a growing political fight. Jeb Bush now saying Donald Trump is just plain wrong for comments he made, calling Mexican illegal immigrants rapists. But Trump says Bush is out of touch and that is not all.

Relief this morning. No terror attacks reported anywhere in the U.S., but officials say there is still reason to be concerned, that this threat is not over.

And hundreds turn out in South Carolina to protest the Confederate flag. But with lawmakers debating its future this week, is there anyway that supporters will be able to keep that flag flying?

BLACKWELL: I'm Victor Blackwell. Good to have you this Sunday morning.

All right. Let's get to it. The war of words this morning between two GOP presidential candidates. Jeb Bush is now offering his most aggressive comments yet on his rival Donald Trump.

KOSIK: Meantime, Trump is wasting no time in firing back at the former Florida governor. This comes more than a week after Trump made headlines, calling immigrants from Latin America rapists.

Let's bring in CNN correspondent Sunlen Serfaty who has more -- Sunlen.

SUNLEN SERFATY, CNN CORRESPONDENT: Good morning to you, Alison.

Well, the fallout over Trump's controversial comments -- well, it continues to dominate so much of the dialogue on the campaign trail. Many of the Republican presidential candidates, they've, of course, denounced Trump's comments and tried to distance themselves from it, but it does seem that it's entering a new level where many of the candidates now are really stepping up their criticism.

Very sharp words coming from Jeb Bush in New Hampshire yesterday. He said he take these comments personally given that his wife is a Mexican and called Trump's words extraordinarily ugly. (BEGIN VIDEO CLIP)

JEB BUSH (R), PRESIDENTIAL CANDIDATE: I don't assume that he thinks that every Mexican crossing the border is a rapist. I mean -- so, he's doing this to inflame and incite and draw attention, which is -- seems to be his organizing principle of his campaign. And it doesn't represent the Republican Party or its values.

(END VIDEO CLIP)

SUNLEN: And Trump has been doubling down and continuing to defend his remarks. And he shot back late last night to the charge that Bush made that he's just trying to get attention for his campaign. And he pointed the finger right back at Jeb Bush saying in a statement, quote, "I never said that all Mexicans crossing the border are rapists. Jeb is mischaracterizing my statements only to inflame."

Now, all of this back and forth comes of course at a time when Republicans are, of course, very eager to make inroads with Hispanic voters. And that's why we've seen as Bush argued, as Mitt Romney also argued this weekend that it's only hurting the GOP's chances, Alison, with this very important group of voters.

The feud now between Jeb Bush and Trump and other candidates, how do you think this is being received by GOP voters?

STEPHEN COLLINSON, CNN POLITICS SENIOR REPORTER: It's very interesting, because all along, the more established candidates have been trying not to get pulled into a public dual with Trump. I guess the rationale for that would be that it only elevates him and damages them with a wider electorate.

It's true that Trump is speaking for a substantial minority, perhaps, of the reason primary electorate. Some people like his comments on immigration. They're against immigration reform. But at some point, I think he's going to have to consider whether these unflattering headlines which he keeps making are actually detracting from the issues he wants to make.

But I think we're going to see what it does is it makes the prospect of the Republican debates a little bit more interesting. We could see some one-on-one clashes between guys like Jeb Bush and Marco Rubio and Donald Trump, and that's going to be interesting.

BLACKWELL: We've got this response from Jeb Bush on Fourth of July in New Hampshire. But it's been 17 days since Donald Trump said that. Any indications of why it took two and a half weeks for a strong response to come from Jeb Bush? COLLINSON: Right. Like I said, they don't really want to get ahead

of Donald Trump, give him more publicity than he's getting already. It is quite sensitive. There is a dilemma for Republican candidates. On the one hand, as Sunlen said, they want to attract the Hispanic electorate. On the other hand, you know, there's a vehement opposition to immigration reform in the Republican Party.

I think what you're seeing now is sort of strength in numbers. A number of candidates have come out condemning Donald Trump. I think that Jeb Bush, the way he did it was quite artful because he was able to come across as defending his wife as much as anything else and that open him a way into this argument that didn't necessarily take on the underlying political issue. So, it's very interesting how long it's taken. I think now, Donald Trump is sort of fairly isolated on this issue.

BLACKWELL: Fairly isolated on this issue, but still number two in many polls, including the latest CNN/ORC poll.

[07:05:01] I mean, the networks are backing away. Companies are backing away. Macy's, one of the major companies, backing away.

How does he sustain this level of support?

COLLINSON: Right. That's very interesting. I mean, if you think about it, the first primary is seven months away. It doesn't seem possible that he could sustain this type of campaign during all those months. Chris Christie said something very interesting this week when he was asked about Donald Trump. And he said if Donald Trump wants to be a serious candidate, he can be a serious candidate.

And I think possibly that Mr. Trump is going to look at the he wants to have a serious candidate or if he wants to be a side show. The way he's gone to this campaign, at least the way he started it, suggested that he doesn't want to be a circus act or a side show and wants to be taken seriously. And so, I think there was some tactical questions that he's probably going to have to consider over the next week or so.

BLACKWELL: All right. Stephen Collinson, thank you so much.

COLLINSON: Thanks.

BLACKWELL: Hey, some of the other presidential candidates are busy this weekend making the rounds on the campaign trail, as one would expect. Several of those presidential hopefuls trying to improve the poll numbers in two key primary states, around a dozen declared candidates were in New Hampshire and Iowa for the Fourth of July holiday -- some arriving to a lot of fanfare, others getting mixed results from their visits.

Stephen back with us.

One of the candidates, Chris Christie, announced his run earlier this week. What does he need to do in New Hampshire or Iowa to boost his position in the polls? COLLINSON: I think New Hampshire is absolutely vital for Christie.

It's almost a one and done state for him. He doesn't have the profile of a candidate who's attractive to evangelical voters that can do really well in Iowa. So, he really does have to make a strong impression in New Hampshire, possibly either winning or very strong seconds, sort of defy expectations that his campaign is not really going to go anywhere.

The good thing in Christie's favor is that New Hampshire prizes the kind of up close, frank campaigning that he's very good at. He's done hundreds of town hall meetings during his time as the New Jersey governor. And hat is exactly the kind of event you have to do in New Hampshire to get your message across .

So, it's a pretty steep climb for Christie in this campaign right now. Once he was seen as a front runner. That's no longer the case but he does have the political tools that you do need to make a good impression in New Hampshire. And the state is going to be very vital to his campaign.

BLACKWELL: All right. Before we let you go, let's hop to the other contest, the Democrats. Hillary Clinton has been criticized for not speaking as often with reporters or answering reporters' questions as some would like. The campaign now dealing with a pretty awkward moment during her stop in New Hampshire in which reporters were roped off. The campaign aides brought the rope out because they were worried they would block the view of people attending the parade, not because they did not want interaction between the candidate and the reporters.

What do you think about this?

COLLINSON: Yes. I guess the optics of this aren't very good for the Clinton campaign. They've been fighting all along this perception that Hillary Clinton doesn't want scrutiny from the press, that she's got something to hide. So, this just plays into that narrative.

On the other hand, there's always going to be tension between reporters who want access all the time to the candidate and the need of the campaign. The campaign would argue that, look, hundreds of people showed up to this parade to see Hillary Clinton. They're trying to put across the impression that she's not this famous person that goes around in a bubble of camera men and Secret Service agents. That she's actually accessible and she wants to talk to people and you can't have journalist just in front of her.

So, it plays into this tension between the press and the candidate. It's not just the legacy of this campaign. It happened in her 2008 campaign and when she was first lady. I think in retrospect, you know, herding the press with a rope like they're farm animals probably didn't create the right impression.

You're not just going to see this through the rest of the campaign but in the White House. In the current administration, there's a great deal of tension between the press and the White House staff on access. So, I think this is something we're going to see continue in the years to come.

BLACKWELL: Yes. Not an easy balance to strike and often does not get better after a candidate is elected.

COLLINSON: Right.

BLACKWELL: Stephen Collinson, thank you so much.

COLLINSON: Thanks.

BLACKWELL: And be sure to watch "STATE OF THE UNION" with Jack Tapper this morning. He will be talking to Republican candidate Mike Huckabee and Democratic candidate Bernie Sanders, live beginning at 9:00 a.m. Eastern, right here on CNN.

KOSIK: And after all the warnings, relief across the U.S. that no terror attacks were reported on July 4th. But the warning remaining in effect. Why the threat isn't over.

Plus, two people are dead, several missing after a pontoon boat overturns. The latest on the search for survivors ahead.

(COMMERCIAL BREAK)

[07:13:07] KOSIK: An increased terror threat forced U.S. leaders at home and abroad to increase security ahead of the July Fourth holiday.

BLACKWELL: And this morning, it seems like the extra measures taken proved successful. Celebrations across the country like the one you see here, the annual fireworks show in New York City, happened with no reported terror-related problems.

Let's go to Washington, where weather was the biggest factor that impacted the day. People there had to even evacuate the National Mall as a precaution during the day. Last night, celebrations went off as planned.

President Obama spoke minutes before the July 4th fireworks. He had a message to those who helped to protect our country.

(BEGIN VIDEO CLIP)

BARACK OBAMA, PRESIDENT OF THE UNITED STATES: On this day, we thank everyone who does so much each and every day to defend our country, to defend our freedom. We are grateful to our armed services. We are grateful to our military families. We are grateful to our veterans. Without you, we could not enjoy the incredible blessings that we do in this greatest country on earth.

(END VIDEO CLIP)

BLACKWELL: So, now what? What about the terror threat moving forward?

For more, let's bring back CNN law enforcement analyst and former FBI assistant director, Tom Fuentes. Tom, we have to strike the balance between vigilance and preparation and a breathless anticipation of crisis. And that may be difficult to strike.

TOM FUENTES, CNN LAW ENFORCEMENT ANALYST: I like your characterization, breathless anticipation. I think there have been a lot of people hyper ventilating over the last couple of weeks of what was to happen.

I'd like to clarify something, Victor. I don't think the increased police presence had anything to do with the fact that we weren't attacked. Many of these ISIS followers want to kill police officers. So that only increased the odds of finding a police officer to kill.

[07:15:02] And the number of crowds that were coming, you know, the people while they're on their way to a secure location, if they're screening at the mall in Washington D.C., or other events around the country, people have to get to that event. They take subway trains, they take busses, they drive, they walk, and they're completely vulnerable at the time.

So, the fact that some crazy ISIS follower chose not to grab a butcher knife and go out the door and attack somebody is not because they chose not to, not because of the measures that were taken. All the security measures are designed to contain an attack, minimize it, but really are going to be in response to an attack. So, if someone or a small group of someone carries out an attack, the police are there to stifle it so that no further attack is made. But people are still vulnerable up to that point.

So, yes, we're not going to be able to stop, we're going to be talking about this next year on July 4th and the year after that and the year after that, because we can't contain the message ISIS puts out and the ability of people to track that message on the Internet and then the ability in their crazy brains to follow it.

KOSIK: You know, Tom, New York Representative Peter King said something interesting this week that there's probably more concern now than any time since September 11th. Why do you think there's this culmination of concern about a possibly event happening?

FUENTES: Well, the concern isn't that we're going to have another 9/11-style attack. I mean, most authorities will tell you it's going to be almost impossible to pull something like that off because of the amount of the command and control, the financing involved. All of the measures involved to pull off on attack like that and coordinate it would make them vulnerable to being intercepted in communications or their finances being intercepted. The fear is, the unknown factor that somebody can take a butcher knife from their kitchen, go out the door and kill somebody and call it an ISIS attack.

Or in this country, the ready availability of guns for everybody. You know, we have 14-year-old gang members killing each other with guns.

So, the fact that it's easy to obtain a firearm or a butcher knife in your kitchen, or a hunting or military knife that big online, you know, makes it -- that you can't stop if you don't know they're going to do it. The ability to know about an attack in advance is greatly reduced when the only person that knows about it is the person that's going to do it.

BLACKWELL: Yes. With the shift from these large scale al Qaeda style attacks to these individuals who are inspired by ISIS. It eliminates a lot of the chatter. So, again that "see something, say something" we've talked about all weekend.

Tom Fuentes, thanks so much.

FUENTES: You're welcome.

BLACKWELL: So, let's talk about what's going on in Greece now. The voters are going to the polls right now. Will this be another bailout they're supporting to solve the debt crisis there. Listen, this is a shakeup either way the vote goes. That could extend from the prime minister's office to your 401(k).

KOSIK: First, having a child born with a fatal genetic disease is heartbreaking. Finding out that disease was detectable is unthinkable. A Georgia couple is sharing their story to save other families from the suffering they have faced.

GUPTA: Seven-year-old Eden can't walk, talk, or do most anything a girl her age should be doing.

(on camera): She has a progressive neurological deficit known as Mucolipidosis Type 4. Thankfully, this is a relatively rare genetic disorder, but it is more common among Ashkenazi Jews.

(voice-over): Eden's development stopped at 18 months. Doctors say she'll be blind by age 12 and will probably not live beyond early adulthood.

CAROLINE GOLD, MOTHER: Every dream that we had for our daughter was just ended with one phone call.

GUPTA: The Golds thought they were thoroughly screened for genetic diseases before they got married. Their first child was born healthy.

CAROLINE GOLD: My doctor tested me for a total of eight diseases and Randy's doctor tested him for a total of two diseases. Neither one of our doctors tested us for ML4.

GUPTA: The couple didn't want other families to suffer the same fate. So, they started an online education and screening program for genetic diseases that are common among Ashkenazi Jews. At-home screening tests are mailed out and a genetic counselor delivers the results over the phone.

RANDY GOLD: JScreen's mission is to provide them information on how to have healthy children of their own.

GUPTA: Just like the Golds who added another daughter to their family.

RANDY GOLD: Eden is here for a purpose. She saves lives every day.

(END VIDEOTAPE)

(COMMERCIAL BREAK)

[07:23:45] BLACKWELL: Twenty-three minutes after the hour. It's time to take a look at other stories making headline this morning.

We're starting with this fire at a chemical plant in Houston that's under investigation.

KOSIK: It broke out late last night. Twelve fire departments and a hazmat crew responded to the scene. While a test in the air quality showed a low risk, residents near the facility were advised to stay indoors and seal up doors and windows. The blaze was put out early this morning. Thankfully, no one was hurt.

BLACKWELL: Authorities in Kentucky are searching for three people missing in the Ohio River. The pontoon boat full of people celebrating the Fourth of July capsized. Two people died. The fire chief says when rescuers arrived at the scene, the pontoon boat was pinned against a work barge. Still no word on why the boat flipped.

KOSIK: In North Carolina, 14 people were injured when their deck to their vacation home collapse. Witnesses told authorities a family was gathering for a photo when the deck gave way and plunged 10 feet to the ground. No word yet on what caused the collapse.

BLACKWELL: Wedding bells for the Piano Man on Saturday. At their annual Fourth of July party, Billy Joel and girlfriend Alexis Roderick surprised guests by exchanging vows. The pair have dated since 2009.

[07:25:01] They are expecting their first child this summer. And this is the fourth marriage for Joel.

KOSIK: Congratulations to them.

The debt crisis coming to a head today in Greece. With the country and broke and its banks on the verge of collapse, will voters choose to accept a bailout to make debt payments? A live report next.

(COMMERCIAL BREAK)

BLACKWELL: Happening now, Greek voters are lining up at the polls deciding the financial future of their country. Greece is on the brink of financial collapse and being offered an emergency bailout by the IMF. But that comes with some extremely tough terms.

Today, voters are deciding whether or not they will accept those terms. A yes vote on today's referendum will allow Greece to continue negotiating for the money. And a no vote would reject the IMF terms and could put Greece on a path to leave the euro as its currency.

We've got with us, journalist Elinda Labropoulou live in Athens for us.

And, Elinda, I wonder, we see these huge yes vote and no vote rallies. They are huge. Are there still some voters who are persuadable, who can be convinced to go from one side of the argument to another?

ELINDA LABROPOULOU, JOURNALIST: Well, that's what the last exit polls suggest. About 10 percent of the voters were undecided the day before yesterday when the last exit polls came out. But the real thing here is that the voters we do know about seem to be neck and neck. We seem to have about the same number of people voting yes and the same number of people voting no.

Now, the confusing part in all this is the actual question, which is not a very clear question. Those voting no are voting no to a bailout, they're voting no to more austerity from the European creditors.